Aiming to establish the relationship between soil characteristcs and floristic composition, 95 fragments of natural vegetation were visited, and their floristic composition was determined by the expedite survey method. A total of 509 tree species belonging to 71 botanic families were found. A detrended correspondence analysis (DCA) and a cluster analysis using relative Sørensen distance showed three floristic groups associated with particular soil types. A multi-response permutation procedure (MRPP) indicated the groups consistence. A main group associated with the basalt derived soils, Purple Latosol and Lytholic soil, could be slipt into two subgroups according to the rock desintegration degree: mesophilous and decidous forest, respectively. The other two groups were linked to the Dark Red and Yellow Red Latosol, the cerradão, and to the Hydromorfic Soil, the swamp forest. Each group presented a characteristic floristic composition. Considering the most abundant tree species, meanly 65% of them showed differential occurrence in the different soil types. A high proportion of species ocurred in few fragments, and each forest remnant presented somewhat regionally rare species. The observed association between soil and remnants floristic composition could contribute to the establishment of criterion for fragment conservation as well as in determining the proper species to choose in vegetation recomposition projects.
forest conservation; forest fragments; Ribeirão Preto; soil-vegetation relationship
